Quote Originally Posted by Deceptus View Post
Best way to do that is to have things available from vendors to create a floor price *cough old materias cough*
Old materia is available from vendors. Not for gil, granted, but it's definitely available.

You can get grade 4, 5, 6, 7, and 8 crafting/gathering materia for scrips (which are also basically free via custom deliveries)

You can get at least grade 6 combat materia for poetics (in Idyllshire).